Prevalence of cutaneous adverse effects of hairdressing - A systematic review

Objective: To identify studies of the prevalence of cutaneous complications of hairdressing in (1) hairdressers and the general population and (2) those more common in people of African ancestry. Data Sources: Three versions of MEDLINE were searched from January 1966 through December 2004 and with a repeated search in August 2005 using 2 groups of search terms: group 1, terms used for hair care and specific study designs: survey, cross-sectional study, and cohort study; group 2, the terms African hair, Afro-Caribbean hair, African American hair, central centrifugal cicatricial alopecia, acne keloidalis nuchae, traction alopecia, and synonyms for each. Study Selection and Data Extraction: All identified cross-sectional and cohort studies of cutaneous adverse effects were included and their quality assessed using criteria developed by Radulescu et al. Data Synthesis: Four studies used either questionnaires or patch testing to estimate the prevalence of cutaneous adverse effects of hair chemicals in the general population and found a prevalence of contact dermatitis, secondary to use of hair dye, of 5.3% and of allergy to paraphenylenediamine of 0.1% to 2.3%. Working as a hairdresser is associated with a prevalence of contact dermatitis ranging from 16.4% in larger cohort studies that included a clinical examination to 80% in the smaller, questionnaire-based studies. Three studies of people of African ancestry found a prevalence of acne keloidalis nuchae ranging from 1.3% to 13.7% and of traction alopecia of 1%. None of these were in the general population. Conclusions: Working as a hairdresser is associated with an increased risk of contact allergy and/or hand dermatitis. Studies of skin disorders of individuals of African ancestry are needed to quantify the health burden and clarify causal variables of these disorders. It is not clear how much the unique shape of the African hair follicle contributes to the development of these conditions.